Dry cask storage Cannot kick this can down the road. Donna Gilmore SanOnofreSafety.org January 2015

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1 Dry cask storage Cannot kick this can down the road Donna Gilmore SanOnofreSafety.org January 2015

2 Game changer Indefinite on-site storage August 26, 2014 NRC approved 60 years (short term) on-site storage 160 years (long term) on-site storage Indefinite on-site storage No other storage sites on horizon U.S. thin steel canisters may start failing within 30 years Some may already have stress corrosion cracks Cannot inspect for corrosion or cracks Cannot repair No early warning monitoring Diablo Canyon Holtec thin canister has conditions for cracking after only two years! Edison plans to spend about $1.3 billion for another thin canister system for San Onofre spent fuel SanOnofreSafety.org 2

3 Two-year old Diablo Canyon Holtec canister has conditions for cracking Temperature low enough to initiate cracks in only 2 years: 85 C (185 F) NRC assumed it would take over 30 years before temperature was low enough NRC proven wrong Temperatures under 85 C allows moist air to dissolve salt on canister Highly corrosive MgCl salts on Diablo canister can trigger corrosion and cracks No technology to inspect for cracks or corrosion We don t know if canisters are cracking or how deep the cracks are We won t know until they crack through the canister wall and release radiation Only small surface areas of 2 canisters were sampled (January 2014) for temperature, salts, and other surface contaminants, due to limited access via concrete overpack air vents No plan in place to replace cracked canisters Canisters not repairable and millions of curies of radiation would be released from even a microscopic crack (Holtec President, Dr. Singh, CEP meeting October 14, 2014) SanOnofreSafety.org 3

4 Thin canisters not what they re cracked up to be Condition of all existing canisters unknown No technology exists to inspect these canisters Canisters in use less than 30 years (1986) Won t know until AFTER leaks radiation Other welded stainless steel items at nuclear plants failed in 11 to 33 years at ambient temperatures ~20 C (68 F) Crack growth about four times faster at 80ºC (176 F) in wicking tests compared with 50 C (122 F) Crack initiation unpredictable Cracks more likely to occur at higher end of temperature range up to 80 C (176 F) instead of ambient temperatures Canister temperatures above 85 C will not crack from marine air chloride salts won t stay and dissolve on canister Many corrosion factors not addressed. NRC focus is chloride-induced stress corrosion cracking (CISCC). SanOnofreSafety.org 4

5 Can t repair thin canisters No current technology to repair canisters filled with spent nuclear fuel Holtec Dr. Singh: should not attempt repair Creates rough surface which becomes a new creation site for corrosion down the road Microscopic cracks can release millions of curies of radiation No plan for replacing cracked canisters or casks Funds not budgeted NRC allows pools to be destroyed, removing only method for replacing canisters and casks Vendor proposal to transport cracked canister in transport cask is unsafe and not NRC approved SanOnofreSafety.org 5

6 No warning before radiation leaks from thin canisters No early warning monitoring Remote temperature monitoring not early warning No pressure or helium monitoring Thick casks have continuous remote pressure monitoring alerts to early helium leak No remote or continuous canister radiation monitoring Workers walk around canisters with a radiation monitor on a stick once every 3 months Thick casks have continuous remote radiation monitoring After pools emptied, NRC allows Removal of all radiation monitors Elimination of emergency planning to communities no radiation alerts Removal of fuel pools (assumes nothing will go wrong with canisters) Humboldt Bay & Rancho Seco pools destroyed Saves utilities millions of dollars Eliminates millions in state and local annual emergency planning funds Eliminates millions for funding of positions and related costs SanOnofreSafety.org 6

7 Thin canisters not designed to be replaced Welded lid not designed to be removed Lid must be unwelded under water Fuel transfer from damaged canister to new canister must be done under water No spent fuel has ever been reloaded into another thin canister Thick casks are designed to remove and reload fuel Potential problem unloading fuel from a dry storage canister or cask into a pool with existing fuel SanOnofreSafety.org 7

8 No defense in depth in thin canisters No protection from gamma or neutron radiation in thin canister Unsealed concrete overpack/cask required for gamma & Neutrons No other type of radiation protection if thin canister leaks Thick steel overpack transfer cask required to transfer from pool Thick steel overpack transport cask required for transport High burnup fuel (HBF) (>45 GWd/MTU) Burns longer in the reactor, making utilities more money Over twice as radioactive and over twice as hot Damages protective Zirconium fuel cladding even after dry storage Unstable and unpredictable in storage and transport Limited technology to examine fuel assemblies for damage Damaged fuel cans vented so no radiation protection Allows retrievability of fuel assembly into another container We are only 1/2 to 5/8 away from a radiation disaster SanOnofreSafety.org 8

9 Thin canisters not ASME certified Canisters do not have independent quality certification from American Society of Mechanical Engineers (ASME) NRC allows exemptions to some ASME standards No independent quality inspections ASME has not developed standards for spent fuel stainless steel canisters SanOnofreSafety.org 9

10 Thin Canisters vs. Thick Casks Safety Features Thick walls Thin canisters 1/2 to 5/8 Thick casks Up to 20 Thin Canister Won t crack Ability to repair Ability to inspect Early warning monitor ASME container certification Thick Cask Defense in depth (redundancy) Stored in concrete building Gamma & neutron protection With concrete overpack Transportable w/o add l cask Market leader U.S. World SanOnofreSafety.org 10

11 Thick casks designed for longer storage Market leader internationally No stress corrosion cracking Maintainable Can inspect Replaceable parts (metal seals, lids, bolts) Double bolted thick steel lids allow reloading without destroying cask 40 years in service with insignificant material aging Thick cask body forged steel or thicker ductile cast iron up to 20 Early warning before radiation leak (remote lid pressure monitoring) Cask protects from all radiation, unlike thin steel canisters. No concrete overpack required. No transfer or transport overpack required Stored in concrete building for additional protection Used as both storage and transport cask ASME & international cask certifications for storage and transport Damage fuel sealed (in ductile cast iron casks) Not currently licensed in U.S. (18 to 30 month process) Vendors won t request NRC license unless they have customer SanOnofreSafety.org 11

12 Germany interim storage SanOnofreSafety.org 12

13 Fukushima thick casks in building SanOnofreSafety.org 13

14 Fukushima thick casks SanOnofreSafety.org 14

15 Sandia Labs: Ductile cast iron performs in an exemplary manner Safe from brittle fracture in transport studies cited show DI [ductile iron] has sufficient fracture toughness to produce a containment boundary for radioactive material transport packagings that will be safe from brittle fracture. Exceeds drop test standards studies indicate that even with drop tests exceeding the severity of those specified in 1 OCFR7 1 the DI packagings perform in an exemplary manner. Exceeds low temperature requirements Low temperature brittle fracture not an issue. The DCI casks were tested at -29 C and -49 C exceeding NRC requirements. Conclusions shared by ASTM, ASME, and IAEA Fracture Mechanics Based Design for Radioactive Material Transport Packagings Historical Review, Sandia Labs, SAND UC-804, April SanOnofreSafety.org 15

16 Problems with thin stainless steel canisters Not maintainable Cannot inspect exterior or interior for cracks Cannot repair cracks Not reusable (welded lid) No warning BEFORE radiation leaks Canisters not ASME certified NRC even allows exemptions from ASME standards No defense in depth Concrete overpack vented Unsealed damaged fuel cans No adequate plan for failed canisters Early stress corrosion cracking risk Inadequate aging management plan SanOnofreSafety.org 16

17 NRC solution Lower aging management standards NRC refuses to evaluate thick casks even though thin canister issues would be resolved Mark Lombard, Director of Spent Fuel Management Division NRC requires first inspection after 25 years Allows 5 years to develop inspection technology Requires inspection of only one canister per plant That same canister to be inspected once every 5 years Allows up to a 75% through-wall crack No seismic rating for cracked canisters No replacement plan for cracked canisters Approves destroying fuel pools after emptied No fuel pools at Humboldt Bay and Rancho Seco No money allocated for replacement canisters NRC standards revision (NUREG-1927) scheduled for sometime in 2015 to address canister aging issues SanOnofreSafety.org 17

18 Recommendations We cannot kick this can down the road Stop procurement of thin canisters Raise U.S. dry storage standards Require best thick cask technology used internationally Base standards on longer term storage needs Not on limitations of thin canister technology Not on vendor promises of future solutions Require bids from thick cask vendors Replace existing thin canisters with thick casks Store in hardened concrete buildings Don t destroy defueled pools until waste stored off-site Install continuous radiation monitors with on-line public access Continue emergency plans until waste is off-site SanOnofreSafety.org 18

19 Donna Gilmore SanOnofreSafety.org

20 Additional Slides SanOnofreSafety.org 20

21 References Diablo Canyon: conditions for stress corrosion cracking in two years, D. Gilmore, October 23, Top Ten Reasons to Buy Thick Casks, D. Gilmore, October 14, pdf Dry Cask Storage Issues, D. Gilmore, September 23, Additional references: SanOnofreSafety.org SanOnofreSafety.org 21

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26 San Onofre Cesium-137 SanOnofreSafety.org 26

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29 Waste is not going anywhere Yucca Mountain geological repository issues unresolved DOE plan: Solve water intrusion issue 100 years AFTER loading nuclear waste Inadequate capacity for all waste Not designed for high burnup fuel Congress limited DOE to consider only Yucca Mountain Funding of storage sites unresolved Communities do not want the waste Poor track record for finding safe waste solutions New Mexico WIPP repository leaked within 15 years Washington Hanford repository leaking containers Other storage sites leaked Inadequate transport infrastructure & potential for accidents High burnup fuel over twice as radioactive, hotter, and unstable Zirconium cladding more likely to become brittle and crack -- eliminates key defense in depth. Radiation protection limited to the thin stainless steel canister. Concrete overpack/cask only protects from gamma and neutrons. Fuel assemblies damaged after storage may not be retrievable Inspection of damaged fuel assemblies is imperfect SanOnofreSafety.org 29

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34 High Burnup Fuel Approval June 1992 Up to 60 GWd/MTU (60 MWD/kg) SanOnofreSafety.org 34

35 Thin canisters cannot be inspected No technology to detect surface cracks, crevice and pitting corrosion in thin canisters filled with nuclear waste Canister must stay inside concrete overpack/cask due to radiation risk, so future inspection technology may be limited Thin canisters do not protect from gamma and neutrons Microscopic crevices can result in cracks Thick casks can be inspected Provide full radiation barrier without concrete Surfaces can be inspected Not subject to stress corrosion cracking SanOnofreSafety.org 35

36 SanOnofreSafety.org 36

37 Recommendations We cannot kick this can down the road Stop procurement of thin canisters Raise U.S. dry storage standards Require best thick cask technology used internationally Base standards on longer term storage needs Not on limitations of thin canister technology Not on vendor promises of future solutions Require bids from thick cask vendors Replace existing thin canisters with thick casks Store in hardened concrete buildings Don t destroy defueled pools until waste stored off-site Install continuous radiation monitors with on-line public access Continue emergency plans until waste is off-site SanOnofreSafety.org 37

38 Thin Canisters vs. Thick Casks Safety Features Thick walls Thin canisters 1/2 to 5/8 Thick casks Up to 20 Thin Canister Won t crack Ability to repair Ability to inspect Early warning monitor ASME container certification Thick Cask Defense in depth (redundancy) Stored in concrete building Gamma & neutron protection With concrete overpack Transportable w/o add l cask Market leader U.S. World SanOnofreSafety.org 38

39 Donna Gilmore SanOnofreSafety.org